Speed limits: is 20 really plenty?

In his blog published in ITS International Alan Dron ask: ‘Is 20 really plenty?’ and explores the complexities of delivering reductions in speeds in urban areas. The article with many international examples highlights the important distinction between a 20mph zone and an area with a 20mph limit. The former includes supporting infrastructure, such as speed bumps, raised areas and chicanes to slow traffic, while a 20mph limit is exactly that – speed limit signs only.